Date: Mon, 16 Jun 2008 14:54:01 +0200 From: Kris Kennaway <kris@FreeBSD.org> To: Martin Cracauer <cracauer@cons.org> Cc: freebsd-fs@FreeBSD.org, cracauer@FreeBSD.org, Jakub Siroky <jakob@dev.citybikes.cz>, freebsd-stable@FreeBSD.org, maxim@FreeBSD.org Subject: Re: infinite loop when copying to ext2fs Message-ID: <48566269.2050001@FreeBSD.org> In-Reply-To: <20080616121609.GA26978@cons.org> References: <20080118120140.2a8170a0@dev> <47921931.9050606@FreeBSD.org> <47921AE2.1060004@FreeBSD.org> <20080301220924.72bf355d@dev.citybikes.cz> <47C9C912.1020700@FreeBSD.org> <20080616034258.GA94873@cons.org> <48563219.9070306@FreeBSD.org> <20080616121609.GA26978@cons.org>
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Martin Cracauer wrote:
> Kris Kennaway wrote on Mon, Jun 16, 2008 at 11:27:53AM +0200:
>> Martin Cracauer wrote:
>>> Kris Kennaway wrote on Sat, Mar 01, 2008 at 10:22:26PM +0100:
>>>> Jakub Siroky wrote:
>>>>> I've just confirmed the same situation on 6.2-RELEASE amd64/GENERIC. I
>>>>> did not noticed it before because I started using ext2fs extensively
>>>>> some months ago.
>>>>>
>>>>> Regards,
>>>>> Jakub
>>>>>
>>>>> On Sat, 19 Jan 2008 16:44:34 +0100
>>>>> Kris Kennaway <kris@FreeBSD.org> wrote:
>>>>>
>>>>>> Kris Kennaway wrote:
>>>>>>> Jakub Siroky wrote:
>>>>>>>> I have two large ext2fs partitions (368 and 313GB) to hold data
>>>>>>>> shared between several OSes. While there were no problems on
>>>>>>>> 6-STABLE branch I was quite disappointed after upgrade to
>>>>>>>> 7-STABLE. Whenever I copy/write to ext2fs partition the system
>>>>>>>> freezes totally without crashdump. So I set debugging settings to
>>>>>>>> kernel config (DEBUG,WITNESS,..) and in console I reproduced error
>>>>>>>> situation ending with full screen of unstoppable running text with
>>>>>>>> lot of memory addresses and a few recognisable words: 'new block
>>>>>>>> bit set for ext already' - again with no crashdump. Then I have
>>>>>>>> formatted 1GB partition with ext2fs and the problem on this small
>>>>>>>> partition appears only sometimes.
>>>>>>> OK, I am able to reproduce this.
>>>>>>>
>>>>>>> Kris
>>>>>>>
>>>>>> Is anyone able to look at this? I could not spot a candidate change
>>>>>> that has not been merged to 6.x.
>>>>>>
>>>>>> Kris
>>>> Sounds like it may have been broken by the change to ext2_bitops.h by
>>>> cracauer. Can you confirm whether backing out 1.2.2.1 fixes it?
>>> I don't think my change can cause a new endless loop.
>>>
>>> I only reversed the order of tests to ensure we don't overrun a page
>>> bounddary (into possibly unmapped space).
>>>
>>> - while(*p == ~0U && ofs < sz) {
>>> + while(ofs < sz && *p == ~0U) {
>>>
>>> It is, however, likely that the code was buggy in the first place.
>>> Linux has replaced all this (the allocation code).
>>>
>>> Also note that the code I fixed is amd64 only. If the endless loop
>>> appears on i386 it's something else.
>>>
>>> Martin
>> It is amd64 only. I am able to reproduce using the method in the
>> original mails, can you?
>
> Didn't try yet, but I did get a probably unrelated panic on ext2fs
> just last week :-) I'll fire it up this week.
>
> How big does the partition have to be to show the problem in this bug?
Sorry, I don't remember. I probably tried it on a md that was a couple
of GB.
Kris
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